Attorney Joe Cotchett, who filed the lawsuit is surrounded by San Jose city officials speaks out during a press conference to discuss the lawsuit at City Hall in San Jose, Calif. on Tuesday June 18, 2013. The city of San Jose has filed a lawsuit against Major League Baseball to get the Oakland A's a new ballpark in the South Bay, the lawsuit will challenge the Giants claim to rights over the region as well as MLB's long-standing monopoly over everything baseball.

Photo: Michael Macor, The Chronicle

Attorney Joe Cotchett, who filed the lawsuit is surrounded by San...

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Attorney's Anne Marie Murphy, Phil Gregory and Joe Cothett with the lawfirm Cotchett, Pitre and McCarthy looking over a copy of the lawsuit in front of City Hall in San Jose, Calif. on Tuesday June 18, 2013, which was filed in Federal Court this morning on behalf of the City of San Jose. The City of San Jose has filed a lawsuit against Major League Baseball to get the Oakland A's a new ballpark in the South Bay, the lawsuit will challenge the Giants claim to rights over the region as well as MLB's long-standing monopoly over everything baseball.

Photo: Michael Macor, The Chronicle

Attorney's Anne Marie Murphy, Phil Gregory and Joe Cothett with...

Image 5 of 6

Attorney Joe Cothett with the lawfirm Cotchett, Pitre and McCarthy in front of City Hall in San Jose, Calif. on Tuesday June 18, 2013, filed the lawsuit in Federal Court this morning on behalf of the City of San Jose. The City of San Jose has filed a lawsuit against Major League Baseball to get the Oakland A's a new ballpark in the South Bay, the lawsuit will challenge the Giants claim to rights over the region as well as MLB's long-standing monopoly over everything baseball.

Photo: Michael Macor, The Chronicle

Attorney Joe Cothett with the lawfirm Cotchett, Pitre and McCarthy...

Image 6 of 6

Attorney Joe Cotchett, who filed the lawsuit is surrounded by city officials speaks out during a press conference to discuss the lawsuit at City Hall in San Jose, Calif. on Tuesday June 18, 2013. The city of San Jose has filed a lawsuit against Major League Baseball to get the Oakland A's a new ballpark in the South Bay, the lawsuit will challenge the Giants claim to rights over the region as well as MLB's long-standing monopoly over everything baseball.

The A's owners' hopes of moving their team from its longtime home in Oakland to a spiffy new ballpark in San Jose ran into trouble Friday in federal court, where a lawyer for the South Bay community struggled to convince a judge that Major League Baseball is illegally blocking the relocation.

"The Oakland A's ... would like to move, but they can't get the three-quarters vote" of club owners that MLB requires to relocate within the San Francisco Giants' designated territory, the city's lead attorney, Joseph Cotchett, said at a hearing in San Jose.

That requirement, he argued, is monopolistic and anticompetitive, in violation of antitrust laws. Although the U.S. Supreme Court declared baseball exempt from antitrust restrictions in 1922, Cotchett said, the exemption has been narrowed by later rulings and congressional action and no longer applies to franchise relocations.

U.S. District Judge Ronald Whyte, who presided over the nearly two-hour hearing, seemed unconvinced.

Noting that the high court has applied the antitrust exemption to "the business of baseball," Whyte asked, "What is the business of baseball if it doesn't include the location of teams?"

"The business of baseball is to compete on the field," Cotchett said. He argued that the Supreme Court had largely repudiated its 1922 ruling and added that the court "is changing the antitrust laws every session they sit."

"That's up to them, not to me," Whyte replied.

The judge did not issue an immediate ruling but appeared to be leaning toward dismissing San Jose's claim that the major leagues would be violating federal law if they continued to thwart the A's move. He promised a decision soon.

A's owners Lew Wolff and John Fisher have been trying for years to move the team out of their aging Oakland ballpark, and signed an option in November 2011 to buy land for a stadium near San Jose's downtown Diridon train station. The A's are not a party to the lawsuit, which San Jose filed in June.

Antitrust rules

The main obstacle to the move is the Giants' right to the territory under provisions of the MLB Constitution that are grounded in baseball's exemption - unique among professional sports - from antitrust laws.

Antitrust laws limit the power of monopolies and allow a would-be competitor to challenge unreasonable restraints of trade, as Oakland Raiders owner Al Davis did when he sued the National Football League and won the right to move to Los Angeles in 1982.

In its 1922 ruling, the U.S. Supreme Court rejected an antitrust suit by the owner of a team in the disbanded Federal League, saying the major leagues were not engaged in interstate commerce and therefore were not subject to antitrust laws. Rulings in 1953 and 1972 disavowed the rationale of that decision but upheld its conclusion on the grounds that Congress had not acted to change the law.

"Baseball has grown and prospered under this regime," John Keker, MLB's lawyer in the case, told Whyte.

"Baseball is different from every other sport," Keker asserted, with a structure that the courts have expressly preserved. Under its rules, he said, "competition is limited to the field," and in other areas, "cooperation is the rule."

In addition to its claim under antitrust law, San Jose's suit argues that the major leagues have violated California law by interfering with the contract between the city and the A's. Phil Gregory, another lawyer for San Jose, said baseball Commissioner Bud Selig had asked the city to put its plans for a stadium on hold until the teams voted on the relocation, but has never scheduled a vote and shows no signs of doing so.

"It's a disruption" of the contract, Gregory argued.

No proof of harm

Keker replied that San Jose's option with the A's was based on speculation about future events and that the city couldn't show it was being harmed, since the proposed stadium site could be sold on the real estate market for more than four times the amount of the A's $7 million option.

Whyte suggested that he may leave the contract issue to state courts if he dismisses the antitrust claim.